As far as the vibe goes, it's nothing like the bay when it comes to tech. LA is way more laid back and people are much less focused on tech. In the bay I constantly overheard people talking about tech or overheard people talking about VC/startups. Rarely ever in LA. The bay is really intense in that way.
I lived in Seattle too. As far as tech scene/startups obsession goes, it was Bay > Seattle >> LA.
With that said, there's a decent community. It's easy to find meetups, etc.